This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
Assuming you are not using a build tool like Maven*: You manipulate the build path by editing the build path in the project properties. You can select what to export there too. If you want to manipulate the runtime configurations you would edit it in menu "Run", "Runtime configurations...".